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Tuesday, April 30, 2013

The CD4017 is a 5-stage divide-by-10 Johnson counter with 10 decoded outputs and a carry out bit.
This library implements a PWM output expander for AVR Atmega micro using CD4017.

With this library we can write a module to move servos using PWM.
A servo expansion module is already implemented as example, with this module you can run up to 36 servos @ 2.25degree precision per step or 9 servos @ 0.18 degrees of precision.
"High accurancy" is 1.0us of precision per step @16Mhz, normal accurancy is 12.5us precision per step @16Mhz.
The default frequency for servos is 50Hz.

If you run this sample at a different frequency you must update the countdown parameter of this library, and also you should test it to prove that the resource are enough to output the pulse to CD4017 at the desired frequency.
I've test it using some servos and scope for the remaining outputs.

This library was developed on Eclipse, built with avr-gcc on Atmega168 @ 16MHz.

Monday, April 22, 2013

This library implements a simple 8x8 led matrix for AVR Atmega.
It uses 16 output ports for the full 8x8 led matrix, but it can be reduced to a smaller matrix, using less ports.
This library was developed on Eclipse, built with avr-gcc on Atmega8 @ 1MHz.

Monday, April 8, 2013

Suddently my dehumidifier stop working, the original humidity switch get broken, it was a mechanical hygrometer, based on a thin transparent strip that react to humidity and engage the main electronic switch. So i decided to build my own dehumidifier board.

AVR dehumidifier is an alternative electronic board for your dehumidifier based upon AVR Atmega8 micro.
When ambient humidity reach the humidify threshold set by the user dehumidifier starts.
A full sensor check the water tank, if it is full the dehumidifier stop running.
An antifrost temperature sensor can shut the compressor down to prevent evaporator frost.
An ambient temperature sensor prevent the dehumidifier to run if temperature is too low or high.